Golf ball covers are routinely marked with various surface indicia, such as the manufacturer's logo and trademark, and the play number, which allows golfers using the same type of golf ball to distinguish one player's ball from that of another. Additional symbols that may also be applied to golf balls include custom figures for promotional purposes as well as specific marks reflecting manufacturing information.
There are different approaches commonly used, mostly water-based or solvent-based printing systems, to add indicia to the dimpled outer surface of a golf ball. One approach involves first creating a decal of the logo or indicia to be printed on the golf ball surface, applying the decal to the spherical, dimpled golf ball surface of the cover, and then spraying the golf ball surface and decal with a clear finish coating. Pad printing is also often used for marking golf ball surfaces, however, very few of the inks employed in pad printing are suitable for use on a golf ball. More specifically, when applied to a golf ball, these inks are not sufficiently durable (impact resistant) to withstand multiple impacts with a golf club. U.S. Pat. No. 6,179,732 discloses a method for applying markings to a golf ball during formation using a two-part mold and a mark-bearing film on the wall of the mold.
During manufacturing of golf balls using conventional printing methods, ink transfer problems are often encountered. For example, in pad printing it is desirable that all of the ink picked up by the printing pad be fully released onto the article to be printed, however, sometimes complete release is not achieved. Consequently, subsequent articles to be printed upon by the same printing pad member can have excessive ink or misaligned ink deposited thereon leading to unwanted ink contamination of balls. Resolution of such problems requires expensive positioning equipment to prevent unwanted contact between balls, between ink depositing members and balls, and between ball handling equipment and balls, respectively.
In addition to the problems associated with ink transfer before the ink is cured or dried, post manufacturing problems are also commonly encountered even after curing takes place. The current water-based inks that work reasonably well for printing on absorbent substrates, such as paper, paperboard, boxboard, and cardboard, do not adhere well to the smooth, nonporous materials typically used in a golf ball. To reduce adherence problems, golf balls generally are subjected to a clear coat covering the golf ball and the printed pattern after an indicia is applied in order to improve appearance as well as to protect the indicia from degradation during the golf ball's normal useful life due to normal play. There are multiple sources of possible degradation to the ball. For example, the ball may be degraded from being struck with a grooved club head or by landing on a rocky or abrasive surface such as a cart path. When adhesion between the protective clear coat and the ink layer of the printed pattern is weak, however, the ink layer can flake, crack, or otherwise degrade more easily under less harsh circumstances. After repeated impacts, such lack of adhesion, toughness, flexibility, and/or hardness yields an unsightly golf ball.
Because a clear coat is typically applied to a golf ball after printing the indicia, custom orders, e.g., imprinting a company logo for a relatively small quantity order, usually requires a special production run that tends to be expensive for the consumer.
Furthermore, water-based coatings, in general, while desirable due to the low toxicity of the solvent, are much harder to evaporate than volatile organic materials, and therefore, are energy intensive, requiring expensive drying ovens to remove the water.
Moreover, coatings and inks used in spraying and pad printing techniques typically involve volatile organic compounds (VOC) found in the compounds used. Manufacturers of printed products may be strongly affected by federal and local regulations that impose restrictions on the emission of VOCs, such as methyl ethyl ketone, acetone, toluene, alcohols, and chlorinated solvents, to the atmosphere.
The prior art describes various methods for the application of indicia to golf balls. For example, U.S. Pat. No. 4,798,386, to Berard, makes reference to white cores and clear covers and even locating decoration on the core to be visible through the clear cover. The Berard concept requires a core which has a satisfactory hue to achieve the desired finished ball coloration. A polybutadiene rubber core of such a color has never been produced and as such, clear cover 2-pc ball have had limited market success.
U.S. Pat. No. 4,998,734 to Meyer, describes a golf ball with a core, a clear cover and “layer interdisposed therebetween.” However, the intermediate layer described is a thin layer of paper or plastic material whose purpose is only to bear textural, alphanumeric or graphical indicia. Meyer teaches that the layer should be sufficiently thin to permit substantial transference of impact forces from the cover to the core without substantially reducing the force.
U.S. Pat. No. 6,462,303 to Brown, describes a method for forming indicia on golf ball covers using laser ablation, i.e., directing a beam of laser radiation onto a portion of the cover and irradiating the cover portion wherein the irradiated cover portion is ablated to form a detectable mark. However, this invention does not disclose non-contact printing of subsurface layers.
U.S. Pat. No. 6,935,240 to Gosetti, describes a method for forming indicia on golf ball components, including covers, cores, intermediate layers, and half shells, using a dye sublimation process. However, the invention does not disclose non-contact printing of a golf ball component.
U.S. Pat. No. 6,949,595 to Morgan et al., discloses a multi-layer golf ball with a translucent polyurea cover, wherein indicia can be printed on an inner layer such that it is visible through the translucent cover. However, the invention does not disclose non-contact printing of the inner layer.
Although each of the above-identified methods may have a specific application for forming indicia on the surface of a golf ball, none is wholly satisfactory. Accordingly, there is a long-felt need for a golf ball marking procedure that will avoid either the inflexibility, or the complexity and expense, inherent in prior art methods for forming indicia on golf ball surfaces. This long-felt problem has now led the Applicants to develop a desirable method for forming indicia on one or more golf ball layers by means of noncontact printing, which advantageously provides increased indicia durability.